Mackay Potash Project

The Mackay Potash Project is forecast to be the world’s lowest cost producer of Sulphate of Potash (SOP). The project demonstrates outstanding Definitive Feasibility Study (DFS) economics with a post-tax real NPV8 of US$655 million and IRR of 21%, based upon a total cash cost of US$159 per tonne FOB and a flat SOP price of US$500 per tonne FOB (Wyndham Port).

The Mackay Potash Project comprises the four key elements of a bulk commodity project being the mine, processing plant, integrated logistics chain and port facility.

World Class Deposit


Sustainable Production


Integrated Efficiency

Logistics Chain

Worldwide Distribution



Lake Mackay is the world’s largest undeveloped sulphate of potash (SOP) brine deposit and contains a drainable mineral resource of 123 million tonnes of SOP.

The project will extract SOP rich brine from shallow infiltration trenches across the lake surface. Brine will flow out of the trench walls and through the trench network assisted by the natural topography of the lake to the main feed canal at the south of the lake.  The main feed canal will then transfer the brine with the assistance of six pumping stations into the evaporation pond system.

The evaporation pond system will comprise nine ponds covering an area of 29km2. Brine will be progressively transferred through this pond system to selectively crystalise specific salt minerals. The pond system has been designed to produce 3.0Mtpa of raw potash salts grading 14% K2O which will be mined by a fleet of five wet harvesters. The harvesters will utilise a cutting auger mounted to both the front and rear of the machine and will autonomously cut precipitated raw potash salts from the pond floor and pump them as a slurry to the processing plant.




The processing plant has been designed to operate at a steady state of 450ktpa of SOP grading 52% K2O. The plant will receive 3.0Mtpa of slurried raw potash salts from the wet harvesters. Test work and process modelling shows a potassium recovery of 82.6% for the process. Importantly the plant design has been specifically designed to operate in the hot, dry conditions of remote Australia.

The slurried raw potash salts received by the plant will be crushed to ensure adequate liberation and then fed into a thickener to minimise the amount of brine that moves forward into the next stages of the process.

In a series of conversion vessels the salt slurry will be converted into a single potash-bearing salt mineral called schoenite. The remaining slurry will only contain schoenite and halite and will be transferred to a flotation circuit.

The flotation circuit will separate the schoenite from the halite and the schoenite will be fed into SOP crystallisers. Here elevated temperatures will dissolve magnesium sulphate (MgSO4) and crystallise SOP (K2SO4). The resulting SOP slurry will be transferred to a hydrocyclone followed by a centrifuge. The SOP will then be dried and stockpiled on site.



Integrated Logistics

Lake Mackay is located 940km by road from its facility at the Port of Wyndham. In combination with Agrimin’s tailored logistics solution it should provide the project with one of the lowest transportation costs in the industry.

Agrimin proposes to construct a dedicated 346km sealed haul road to connect the Lake Mackay site with the public road network.

The Company has formed a joint venture called Newhaul Bulk with experienced WA bulk logistics operator Mr Craig Mitchell. The 50:50 incorporated joint venture will provide road haulage and road maintenance services for the Mackay Potash Project and crucially brings an important operational capability to Agrimin’s logistics chain.

A customised fleet of ~24 road trains will transport 450ktpa of SOP from Lake Mackay to Wyndham Port.

Lake Mackay is the world’s largest undeveloped sulphate of potash (SOP) brine deposit and contains a drainable mineral resource of 123 million tonnes of SOP.




The proposed facility at Wyndham Port completes Agrimin’s fully integrated logistics chain. It will comprise of truck unloading, storage and barge loading facilities with a focus on minimising product rehandling and simplifying the shiploading process.

The port facility will be located on a 17 hectare waterfront property which is currently held by Agrimin under an Option Agreement to purchase.

The facility will provide Agrimin with a bulk shiploading solution that is specifically tailored for the Company’s SOP product. The barge load out facility will allow Agrimin to export its products in a range of cargo sizes upto Ultramax (62,000 DWT).



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